Digging 40cm Down — and Renting X-Ray Vision for ₩6,500

Day thirty-three. A day spent mostly below floor level, learning what moving a bathroom actually costs in earth.

Why the digging is deep. Yesterday we learned the principle the hard way: the toilet’s soil pipe — where waste exits the building — cannot move. What moves is everything else, which means excavating a channel from the new toilet position back to the existing pipe, deep enough for the connecting drain to fall continuously toward it. Our plumber’s spec: at least 40 cm below the old floor, deeper the farther the fixture travels. So we dug — jackhammer through the tile and mortar crust, then mercifully into soil, where the shovel takes over. Reaching the soil layer is the battle; after that it’s just labor.

Four bathrooms deep. The annex bathroom revealed this old house’s renovation habit in cross-section: every past remodel had tiled over the existing tile. Four layers, roughly 15 cm of accumulated floor, impervious to ordinary demolition. The technique that cracked it: drill vertically down at a spot safely clear of any plumbing until you reach true soil — establishing a full-depth reference hole — then work the hammer drill outward from that free edge. Layers that resist a frontal assault peel away sideways. Wall tile came off too, exposing the supply runs; the plumber will arrive to a bathroom he can read at a glance.

₩6,500 of foresight. Before future floor work anywhere else in the house, we rented a thermal imaging camera — ₩6,500 a day. Run the underfloor heating, watch the pipes glow on screen, and suddenly the invisible is drawn on the floor: every heating loop, mapped. In the bath zone we cleaned the slab and penciled the pipe routes directly onto the concrete. One burst heating line during later work would cost a hundred times the rental.

Elsewhere: four more insulation boards up in the corridor. The house is being worked at every altitude — under its floors, on its walls.